title: Heterogeneous cerebral vasoreactivity dynamics in patients with carotid stenosis.
abstract: Cerebral vasoreactivity (CVR) can be assessed by functional MRI (fMRI) using hypercapnia challenges. In normal subjects, studies have shown temporal variability of CVR blood oxygenation level-dependent responses among different brain regions. In the current study, we analyzed the variability of BOLD CVR dynamics by fMRI with a breath-holding task in 17 subjects with unilateral carotid stenosis before they received carotid stenting. Great heterogeneity of CVR dynamics was observed when comparing BOLD responses between ipsilateral and contralateral hemispheres in each patient, especially in middle cerebral artery (MCA) territories. While some subjects (n=12) had similar CVR responses between either hemisphere, the others (n=5) had a poorly correlated pattern of BOLD changes between ipsilateral and contralateral hemispheres. In the latter group, defined as impaired CVR, post-stenting perfusion tended to be more significantly increased. Our data provides the first observation of divergent temporal BOLD responses during breath holding in patients with carotid stenosis. The development of collateral circulation and the derangement of cerebral hemodynamics can be detected through this novel analysis of the different patterns of BOLD changes. The results also help in prediction of robust increase of perfusion or hyperperfusion after carotid stenting.
authors.affiliation: Department of Neurology, Stroke Center, Chang Gung Memorial Hospital, Linkou Medical Center and College of Medicine, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Ting-Yu
authors.initials: TY
authors.lastname: Chang
authors.forename: Wan-Chun
authors.initials: WC
authors.lastname: Kuan
authors.forename: Kuo-Lun
authors.initials: KL
authors.lastname: Huang
authors.forename: Chien-Hung
authors.initials: CH
authors.lastname: Chang
authors.forename: Yeu-Jhy
authors.initials: YJ
authors.lastname: Chang
authors.forename: Ho-Fai
authors.initials: HF
authors.lastname: Wong
authors.forename: Tsong-Hai
authors.initials: TH
authors.lastname: Lee
authors.forename: Ho-Ling
authors.initials: HL
authors.lastname: Liu
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001808:Blood Vessels / Q000502:physiology*; D001921:Brain / Q000098:blood supply*; D062485:Breath Holding; D002245:Carbon Dioxide / Q000097:blood; D016893:Carotid Stenosis / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged
chemical_list: D002245:Carbon Dioxide